The present invention relates to a low fat peanut butter-like product and, more particularly, to such a low fat peanut butter-like product that is shelf stable at room temperatures. The present invention also relates to a method for producing the above low fat peanut butter-like product.
Peanut butter is one of the most popular foods in American diet. It is enjoyed for its rich flavor and unique texture and mouth feel. While peanut butter is generally a healthy food, it is high in both fat and calories. A 32 gram portion of conventional peanut butter typically contains about 190 calories, at least 70 percent of which are from fat. For many people who are obese or who have medical problems, low calorie, low fat diet are imperative. Further, it is well documented that most of the U.S. population consumes too much fat and many people who do not have medical problems nonetheless choose to reduce their fat intake.
Some reduced calorie and reduced fat peanut and peanut flour products have been created. In these products, calories are reduced by partially removing fats from the peanuts or peanut flours. Unfortunately, this means of caloric reduction sacrifices certain desirable sensory properties. For example, the reduced fat peanut flours described in U.S. Pat. Nos. 4,113,599 and 3,947,599 are very bland and almost tasteless. Further, these products are typically dry, generally having a water content of under 5 percent by weight. As a consequence, the use of these products has been limited to base protein materials which are used in the production of other food products.
U.S. Pat. No. 4,828,868 ("the '868 patent"), issued to the present inventors on May 9, 1989 and incorporated by reference into this specification, discloses a low fat (70-95% less fat than conventional peanut butter), low calorie peanut butter type product of processed defatted peanut flour and water (plus other ingredients). The product of the '868 patent is not shelf stable at room temperatures, however, and requires refrigeration during all stages of storage after packaging, both before and after opening.
Since consumers are accustomed to conventional peanut butter being marketed on unrefrigerated grocery shelves and being storable for an extended period at home without refrigeration, it is desirable from a marketing standpoint that a low fat, low calorie peanut butter-like product be similarly shelf stable at room temperatures.
The book, Food Science, by Norman N. Potter, Third Edition, A.V.I.(1984) describes the term "water activity level". Qualitatively, water activity is a measure of unbound, free water in a system that is available to support biological and chemical reactions. Since water activity is not the same as absolute water content, two foods with the same water content can have very different water activities. That is, the water activity level depends on the degree to which water is free or otherwise bound to food constituents. When a food is in moisture equilibrium with its environment, the water activity of the food will be quantitatively equal to the relative humidity in the head space of the container divided by 100.
In general, as the water activity (A.sub.w) of a food product increases, its shelf life decreases. That is, the food product becomes more susceptible to mold, fungus, and bacterial growth as the water activity increases. The U.S. Food and Drug Administration defines a low acid food product with a pH of greater than 4.6 as "shelf stable" if it has a water activity of 0.85 or less. All of the products described in the '868 patent have water activities over 0.95 and usually over 0.97.
Moreover, besides requiring constant refrigeration (both before and after opening), the peanut butter-like products made in accordance with the '868 patent lack the rich taste and desirable mouth feel that typically characterize real peanut butter. This is due in part to the peanut ingredient disclosed in the '868 patent being defatted peanut flour. Defatted peanut flours are relatively bland and deliver limited peanut flavor.
In order to improve the flavor and mouth feel of the peanut butter-like products made in accordance with the '868 patent, natural peanut butter was added to the product in quantities sufficient to increase the sensory qualities but to still permit the product as a "low fat product". This proved to be unacceptable as the addition of conventional peanut butter to the product having a water activity in excess of 0.95 resulted in the rapid deterioration of the flavor and texture of the product.
Recently, there have been developed reduced fat peanut butter-like products containing 10%-30% less fat than conventional peanut butter and middle range peanut butter-like products containing 30%-50% less fat than conventional peanut butter. Some of these products have relatively low water activities and thereby acceptable shelf stability. For example, U.S. Pat. No. 5,240,734 discloses such a reduced fat peanut butter-like composition that has a water activity which is satisfactory for shelf stability. The composition includes peanut butter in the amount of 50% by weight. Accordingly, while the composition has less fat than conventional peanut butter, it still does not approach the FDA requirements for a low fat product. Specifically, the FDA requires such a product to contain 3.0 or less grams of fat per 32 gram serving or at least 80-95% less fat than conventional peanut butter.
U.S. Pat. No. 5,366,754 is directed to a reduced fat peanut butter-like product and a method of making the same. This patent suggests that it provides a method for producing a peanut butter-like product that has a low fat content and a water activity of 0.91 after pasteurization. However, the peanut raw materials utilized to make this "low fat" product are not commercially available. Further, a water activity level of 0.91 reported for that product does not denote a shelf stable product according to U.S. FDA standards.